ANSYS Based FEM Analysis for Three and Four Coil Active Magnetic Bearing - A Comparative Study

The active magnetic bearing (AMB) is an integral part of the industrial rotational machine. The paper deals with simulation study of three and four coil AMB utilizing Finite Element Method (FEM). This paper also presents how ANSYS software (Ver. 12.1) can be used to perform the magnetic field analysis in the AMB. This work reports ANSYS simulation for two different structure of AMB that uses three and four attraction type magnets placed in 120 and 90 degree apart from each and other respectively. Three and four attractive magnets give an unstable static force, decreasing with greater distance, and increasing at close distances between electromagnet (stator) and rotor. The nonlinear solution of the magnetic vector potential is determined by using the 2-D finite element method. The force is calculated by Maxwell’s stress tensor method. The electromagnetic field distribution and density analysis allow verifying the designed AMB and the influence of the shaft and coil current changes on the bearing parameters.